Winner of the Rockower Award, the highest honor in Jewish journalism, this blog contains random musings of a journalist, father, husband, son, friend, poodle-owner, Red Sox fan and occasionally-ranting rabbi, taken from Shabbat-O-Grams, columns, speeches, letters, sermons and thin air. "On One Foot," the column, appears regularly in the New York Jewish Week, as well as a blog for the "Times of Israel."

For ages we’ve been obsessed with the question, “Who is a Jew?” Perhaps we need to be asking instead, “Who isn’t?”

A team of geneticists has uncovered explicit evidence of mass conversions of Sephardic Jews to Catholicism in 15th- and 16th-century Spain and Portugal. The study, based on an analysis of Y-chromosomes and reported first in the American Journal of Human Genetics, indicates that 20 percent of the population of the Iberian Peninsula has Sephardic Jewish ancestry. That’s about 10 million people. While anti-Semitism remains pervasive and the Jewish population microscopic, there is a deep fascination with all things Jewish. “We’ve gone from a period of pillaging the Jews and then suppressing and ignoring their patrimony to a period of rising curiosity and fascination [about them],” said Anna Maria Lopez, the director of Toledo’s Sephardic Museum in a New York Times interview.

So while there are almost no Jews left in Spain, a residue remains, literally in their DNA. Everyone’s a little bit Jew-ish, even if almost no one is a Jew.

The suffix “ish,” indicating approximation, is increasingly popular among today’s youth, according to the language forum, “Wordreference.com.” Kids are constantly tossing it about: A movie is “creepish,” he looks “Europeanish,” the dress is “greenish” and the meeting begins at “five-ish.” In an age where fluidity is the norm, and everything, from the national debt to Arlen Specter’s party affiliation, is a moving target, we all need to learn how to go with the flow. Fortunately, we Jews are uniquely prepared to do just that: We already have “ish” in our name.

The Pew Foundation’s latest survey on the American religious landscape, called, “Faith in Flux: Changes in Religious Affiliation in the U.S.,” notes that Americans change religions almost as often as they change their underwear, with over half abandoning their childhood faith-group, usually before the age of 24.

Meanwhile, Synagogue 3000’s latest survey indicates that American Jews are foregoing secular and ethnic identification in favor of a more “spiritually oriented” — and therefore more fluid — self-definition. The survey notes that the presence of Christian, or formerly Christian, members in many Jewish households has led to a greater comfort level with spiritual ideas and language. While there are some forms of spirituality that are innately Jewish, the category lends itself to a blurring of boundaries between faiths. In the S3K report, Rabbi Rachel Cowan states that spirituality “helps me see that I’m not the whole story here, that I’m just part of something much bigger.” Bigger even than Jewish peoplehood.

Prior Pew surveys have shown how Jews have been more successful than other groups in stemming the tide of assimilation. But with sectarian lines dissolving rapidly, in a century or two, how many more millions of non-Jewish Americans will be searching their family trees for Jewish ancestry? On the other hand, how many non-Jewish seekers will stop off for a nosh at a Shabbat Kiddush on the road to Damascus and never leave?

Theodore Herzl was one of the most important Jews of all time. Yet none of his three children was Jewish and only one descendant, a grandson, was a Zionist — and he committed suicide. Nancy Pelosi has Jewish grandchildren. Eight of Moses Mendelssohn’s nine grandchildren were baptized. Thomas Jefferson reportedly had Jewish ancestors and African-American descendants. We’ve become the La Guardia Airport of faith traditions; so many coming in, so many going out.

Fiorello La Guardia had a Jewish parent, in fact, as does Sean Penn. There’s a cottage industry out there identifying famous half-Jews, including Web sites like www.halfjew.com and www.half-jewish.net. Who knew?

The Herzl family history was tragic, but no more so than the ancestry of King David. His great grandmother was Ruth, a Moabite, whose on-the-fly conversion following the tragic deaths of her husband and brother-in-law will be recalled on Shavuot this weekend. It is likely that Ruth’s simple loyalty oath would not be recognized as a conversion by the Israeli rabbinate today, which would place David’s Jewish identity into question as well. Since tradition holds that the Messiah will come from David’s seed, though, even the Israeli rabbinate would hesitate to go there.

A Midrash states that every Jew was present at Sinai, including all future generations. If David and Ruth were there, what about Fiorello, Sean and Jefferson? What about 10 million Iberians, whose only crime was that their ancestors were forced to convert? We can’t retroactively crop them out of the Sinai family picture.

I subscribe to traditional standards in determining Jewish identity, but the world has become far too complicated to ignore everyone else. So, yes, there are Jews, the ones who fall within normative halachic parameters; and then there are those who are Jew-ish, a group that includes many millions more.

The basis for Ruth’s avowal of loyalty was “chesed,” an unconditional love going beyond the letter of the law. We need to employ lots of chesed in reaching out beyond the scope of those who are Jews, to include also those who are generations removed from their last Shavuot blintz, to those who are Jew-ish.That’s because they need us. Judaism does have something unique to offer, something that goes beyond survival and adaptability. We are the ones, after all, who invented chesed.

As a census year approaches and we ponder how to tally our people, let’s think bigger — much bigger than simply counting those at the core or even those at the so-called periphery. Let’s look way beyond that farthest fringe, to those millions of once-were Jews, whose spiritual search will inexorably lead them back to our doors.